Question

Two separate bulbs contain gas A and gas B. The density of gas A is twice as that of B. The molecular mass of A is half as that of B. If temperature is constant, the ratio of the pressure of A and B is

• A. 1:01
• B. 1:02
• C. 4:01
• D. 2:01

Answer 1

Answer: (C)

4:01

Answer 2

$d=\frac{PM}{RT}$ Given : $\frac{d_{A}}{d_{B}}=2,\, \frac{M_{A}}{M_{B}}=\frac{1}{2}$ $\frac{d_{A}}{d_{B}}=\frac{P_{A}M_{A}}{RT}\times\frac{RT}{P_{B}M_{B}}=2\,\,\Rightarrow\,\, \frac{P_{A}}{P_{B}}\times\frac{M_{A}}{M_{B}}=2$ $\Rightarrow\,\, \frac{P_{A}}{P_{B}}\times\frac{1}{2}=2\,\,\Rightarrow\,\, \frac{P_{A}}{P_{B}}=4:1$